Re: macro syntax-error works in prefix but not curly-infix

[adriano]

Il giorno sab, 04/09/2021 alle 16.41 +0200, Damien Mattei ha scritto:
> hi,
> 
> i have this macro:
> 
> (define-syntax <+
>   (syntax-rules ()
>     ((_ var expr) (define var expr))
>     ((_ err ...) (syntax-error "Bad <- form")) ;; does not work in
> infix !
>     ))
> 
> why my syntax-error pattern never reach in infix:
> 
> scheme@(guile-user)> {x <+ 7 8}
> While compiling expression:
> Syntax error:
> unknown file:3:3: source expression failed to match any pattern in
> form <+
> 
> but ok in prefix:
> 
> scheme@(guile-user)> (<+ x 9 10)
> While compiling expression:
> Syntax error:
> unknown location: <+: Bad <- form in form (<+ x 9 10)
> 
> why?
> Regards,
> Damien


As far as I understand, infix syntax can't be achieved through macros

You'd need a custom reader for that

I might be wrong, but at least I offered something